# What is Electric Current? Definition and Types

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Electric current definition is the rate of flow of electric charge through a conducting medium with respect to time. Electric current definition is also the rate of flow of charge in respect of time when there is a potential difference appeared between two points in a conductive medium electric charge starts flowing from higher potential point to lower potential point to balance the charge distribution between the points. Or Electric current definition is electric charge in motion. It can take the form of a sudden discharge of static electricity, such as a lightning bolt or a spark between your finger and a ground light switch plate.

As the current is the ratio of transferred charge to the time taken for this charge transferring we can say one unit current is such a rate of charge transferring in which one Coulomb charge is transferred from one point to another in one second. Hence, unit of current is coulomb / second and it is well known as ampere after the great physicist Andrew Marie Ampere. This is SI unit of electric current.

# What is Electric Current? Definition and Types of Current

As the current is the ratio of transferred charge to the time taken for this charge transferring we can say one unit current is such a rate of charge transferring in which one Coulomb charge is transferred from one point to another in one second. Hence, unit of current is coulomb / second and it is well known as ampere after the great physicist Andrew Marie Ampere. This is SI unit of electric current.

## Electric Current Formula

If q Coulomb electric charge gets transferred between these two points in time t sec, then the current can be calculated as:

In differential form, the current can be represented as:

Those are electric current formula between two points in time t sec and In differential form.

## Types of Current

Current has 4 types, The types of currents are Direct Current, Alternating Current, Magnetic Effect of Current, and Current in Magnetic Field. So, I will explain how types of current works.

### Direct Current

When current flows in one direction either in constant or fluctuating manner the current is called direct current.

### Alternating Current

When current flows in either direction alternatingly in a frequency is called alternating current. The average value of an alternating current is zero. The alternating current is measured in RMS value. One main parameter of alternating current is frequency.

### Magnetic Effect of Current

When current flows through a conductor there will be a magnetic field surrounding the conductor. The direction of the lines of force of the magnetic field can be determined by right-hand grip rule.

If we imagine that we have held the current carrying conductor with our right hand with extended thumb along the direction of the current then four fingers of our right hand indicate the direction of lines of force of the magnetic field.

When we make a coil with a conductor and current flows through the coil then due to magnetic effect of each conductor of the coil there will be an overall magnetic field surrounding the coil.

Here we can also determine the direction of the field by right-hand grip rule. If we hold the current carrying coil with our four fingers along the direction of current in the turns of the coil then the extended thumb indicates the direction of the magnetic field.

### Current in Magnetic Field

When we place a current carrying conductor or a current carrying coil in a magnetic field, a mechanical force acts on the current carrying conductor or coil. This mechanical force depends on the current through the conductor or coil.

### Measurement of Current

Depending on the principle of interaction between current and magnetic field one can measure the current. One of the basic instruments to measure the current is pmmc instrument or permanent magnet moving coil instrument.

The pmmc instrument is only able to measure direct current. The alternating current can be measured by moving iron instrument where magnetic field created by current through the instrument coil causes movement of a soft iron piece either by attraction or repulsion force.

This instrument can also measure direct current. Rectifier type instruments are also used to measure alternating current. Here bridge rectifier is used to rectify alternating current then it is measured with pmmc instrument.

Wherever may be the types of current measuring instrument in one word all current measuring instruments are called ammeter. An ammeter is always connected in series with the path of which the current to be measured. When very high current is to be measured we use current transformers to step down current for measuring purpose.

### Electric Current Definition and Types of Current

Electric current definition brings us to an important feature of electric current: it can do work. It can light your home, wash and dry your cloths, and even raise your garage door at the flip of the switch.